A Digital Addressable Lighting Interface (DALI) is a data and protocol standard for lighting and/or related equipment (e.g., ballasts, dimmers, photoelectric cells, transformers, motion detectors, etc.). DALI compatible equipment can be interconnected on a DALI bus, even if from different manufactures and of different lighting technologies. DALI requires a single pair of wires as the communication bus to all devices on the same DALI network. All devices connected to the network can be addressed by a broadcast message, or individual devices can be controlled with a unique bus address.
A DALI network can include a controller and one or more lighting and/or related equipment devices having DALI interfaces. In some implementations, a DALI system can include a luminaire control unit (LCU), a luminaire (which can include a control unit and a LED light engine), and a data concentrator unit (DCU).
The LCU can wirelessly communicate with the DCU via radio frequency transmissions (e.g., typically in the range 869.4-869.65 MHz, at 500 mW). The LCU can be series connected via wires/cables between a line voltage power source and the luminaire control unit. The LCU can switch off the luminaire by interrupting the line voltage power to the luminaire control unit. Additionally, the LCU could also include connections to the luminaire control unit via the DALI network.
Individually, a conventional luminaire and a conventional LCU can each fulfill typical electromagnetic compatibility (EMC) requirements for spurious harmonic generation/suppression. However, when integrated at a system level this conventional equipment fails to meet specified EMC standards. When the LCU is active, RF communication with the DCU is non-predictable. The RF communication from the LCU to the DCU can cause generation of the unwanted harmonics. Further, the LCU's control of line voltage power to the luminaire control unit can result in high peak-current spikes, which themselves can generate unwanted harmonics. Thus, at a system level EMC standards are not often met by a DALI network containing an LCU, a DCU, and a luminaire.